Photothermal Microscopy and
Spectroscopy Webinar

Chromatin organization and dynamics are pivotal aspects governing the regulation of nuclear processes within cells, yet observing these chromatin nanostructures quantitatively and continuously in live cells has presented a formidable challenge. The predominant approach in current cell research involves fluorescence-based microscopy, leveraging the labeling of fluorophores to achieve spatial resolution and detection sensitivity. While successful, this method grapples with issues like photobleaching and labeling artifacts, limiting its ability to provide a clear, real-time view of nanoscopic organization within living cells.

In this presentation, an innovative strategy for probing nanoscale chromatin configurations within the cell nucleus will be introduced, utilizing dynamic light scattering (DLS) imaging. Interferometric scattering microscopy in transmission, coherent brightfield microscopy (COBRI), was developed to record the time-varying linear scattering signals emitted by unlabeled chromatin while under laser illumination. This robust scattering signal enabled high-speed, continuous imaging with sub-millisecond time resolutions. The combination of sensitivity and rapid data acquisition empowered the capture of DLS signals from native biomolecules within live cellular environments. Analysis of these signals allowed for the determination of nanoscopic chromatin domain sizes and their diffusion coefficients.

The novel DLS approach was employed to investigate dynamic chromatin remodeling across various cell activities, encompassing different cell cycle phases and gene transcription processes. The talk concludes by highlighting the broader applicability of DLS analysis in label-free bioimaging, which promises to revolutionize single-cell profiling by providing ultrahigh-content insights into cellular behavior.